diff options
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/atomic.h | 12 | ||||
| -rw-r--r-- | arch/x86/include/asm/atomic64_32.h | 79 | ||||
| -rw-r--r-- | arch/x86/include/asm/atomic64_64.h | 12 | ||||
| -rw-r--r-- | arch/x86/include/asm/cmpxchg_32.h | 205 | ||||
| -rw-r--r-- | arch/x86/include/asm/cmpxchg_64.h | 8 | ||||
| -rw-r--r-- | arch/x86/include/asm/qspinlock.h | 13 | ||||
| -rw-r--r-- | arch/x86/include/asm/qspinlock_paravirt.h | 7 |
7 files changed, 201 insertions, 135 deletions
diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h index 55a55ec04350..55b4d24356ea 100644 --- a/arch/x86/include/asm/atomic.h +++ b/arch/x86/include/asm/atomic.h @@ -86,11 +86,7 @@ static __always_inline int arch_atomic_add_return(int i, atomic_t *v) } #define arch_atomic_add_return arch_atomic_add_return -static __always_inline int arch_atomic_sub_return(int i, atomic_t *v) -{ - return arch_atomic_add_return(-i, v); -} -#define arch_atomic_sub_return arch_atomic_sub_return +#define arch_atomic_sub_return(i, v) arch_atomic_add_return(-(i), v) static __always_inline int arch_atomic_fetch_add(int i, atomic_t *v) { @@ -98,11 +94,7 @@ static __always_inline int arch_atomic_fetch_add(int i, atomic_t *v) } #define arch_atomic_fetch_add arch_atomic_fetch_add -static __always_inline int arch_atomic_fetch_sub(int i, atomic_t *v) -{ - return xadd(&v->counter, -i); -} -#define arch_atomic_fetch_sub arch_atomic_fetch_sub +#define arch_atomic_fetch_sub(i, v) arch_atomic_fetch_add(-(i), v) static __always_inline int arch_atomic_cmpxchg(atomic_t *v, int old, int new) { diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h index 3486d91b8595..40ff73b5ec55 100644 --- a/arch/x86/include/asm/atomic64_32.h +++ b/arch/x86/include/asm/atomic64_32.h @@ -14,6 +14,32 @@ typedef struct { #define ATOMIC64_INIT(val) { (val) } +/* + * Read an atomic64_t non-atomically. + * + * This is intended to be used in cases where a subsequent atomic operation + * will handle the torn value, and can be used to prime the first iteration + * of unconditional try_cmpxchg() loops, e.g.: + * + * s64 val = arch_atomic64_read_nonatomic(v); + * do { } while (!arch_atomic64_try_cmpxchg(v, &val, val OP i); + * + * This is NOT safe to use where the value is not always checked by a + * subsequent atomic operation, such as in conditional try_cmpxchg() loops + * that can break before the atomic operation, e.g.: + * + * s64 val = arch_atomic64_read_nonatomic(v); + * do { + * if (condition(val)) + * break; + * } while (!arch_atomic64_try_cmpxchg(v, &val, val OP i); + */ +static __always_inline s64 arch_atomic64_read_nonatomic(const atomic64_t *v) +{ + /* See comment in arch_atomic_read(). */ + return __READ_ONCE(v->counter); +} + #define __ATOMIC64_DECL(sym) void atomic64_##sym(atomic64_t *, ...) #ifndef ATOMIC64_EXPORT #define ATOMIC64_DECL_ONE __ATOMIC64_DECL @@ -61,12 +87,18 @@ ATOMIC64_DECL(add_unless); #undef __ATOMIC64_DECL #undef ATOMIC64_EXPORT -static __always_inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 o, s64 n) +static __always_inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new) { - return arch_cmpxchg64(&v->counter, o, n); + return arch_cmpxchg64(&v->counter, old, new); } #define arch_atomic64_cmpxchg arch_atomic64_cmpxchg +static __always_inline bool arch_atomic64_try_cmpxchg(atomic64_t *v, s64 *old, s64 new) +{ + return arch_try_cmpxchg64(&v->counter, old, new); +} +#define arch_atomic64_try_cmpxchg arch_atomic64_try_cmpxchg + static __always_inline s64 arch_atomic64_xchg(atomic64_t *v, s64 n) { s64 o; @@ -195,69 +227,62 @@ static __always_inline s64 arch_atomic64_dec_if_positive(atomic64_t *v) static __always_inline void arch_atomic64_and(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c & i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val & i)); } static __always_inline s64 arch_atomic64_fetch_and(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c & i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val & i)); - return old; + return val; } #define arch_atomic64_fetch_and arch_atomic64_fetch_and static __always_inline void arch_atomic64_or(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c | i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val | i)); } static __always_inline s64 arch_atomic64_fetch_or(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c | i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val | i)); - return old; + return val; } #define arch_atomic64_fetch_or arch_atomic64_fetch_or static __always_inline void arch_atomic64_xor(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c ^ i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val ^ i)); } static __always_inline s64 arch_atomic64_fetch_xor(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c ^ i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val ^ i)); - return old; + return val; } #define arch_atomic64_fetch_xor arch_atomic64_fetch_xor static __always_inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v) { - s64 old, c = 0; + s64 val = arch_atomic64_read_nonatomic(v); - while ((old = arch_atomic64_cmpxchg(v, c, c + i)) != c) - c = old; + do { } while (!arch_atomic64_try_cmpxchg(v, &val, val + i)); - return old; + return val; } #define arch_atomic64_fetch_add arch_atomic64_fetch_add diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h index 3165c0feedf7..ae12acae5b06 100644 --- a/arch/x86/include/asm/atomic64_64.h +++ b/arch/x86/include/asm/atomic64_64.h @@ -80,11 +80,7 @@ static __always_inline s64 arch_atomic64_add_return(s64 i, atomic64_t *v) } #define arch_atomic64_add_return arch_atomic64_add_return -static __always_inline s64 arch_atomic64_sub_return(s64 i, atomic64_t *v) -{ - return arch_atomic64_add_return(-i, v); -} -#define arch_atomic64_sub_return arch_atomic64_sub_return +#define arch_atomic64_sub_return(i, v) arch_atomic64_add_return(-(i), v) static __always_inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v) { @@ -92,11 +88,7 @@ static __always_inline s64 arch_atomic64_fetch_add(s64 i, atomic64_t *v) } #define arch_atomic64_fetch_add arch_atomic64_fetch_add -static __always_inline s64 arch_atomic64_fetch_sub(s64 i, atomic64_t *v) -{ - return xadd(&v->counter, -i); -} -#define arch_atomic64_fetch_sub arch_atomic64_fetch_sub +#define arch_atomic64_fetch_sub(i, v) arch_atomic64_fetch_add(-(i), v) static __always_inline s64 arch_atomic64_cmpxchg(atomic64_t *v, s64 old, s64 new) { diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h index b5731c51f0f4..ed2797f132ce 100644 --- a/arch/x86/include/asm/cmpxchg_32.h +++ b/arch/x86/include/asm/cmpxchg_32.h @@ -3,103 +3,150 @@ #define _ASM_X86_CMPXCHG_32_H /* - * Note: if you use set64_bit(), __cmpxchg64(), or their variants, + * Note: if you use __cmpxchg64(), or their variants, * you need to test for the feature in boot_cpu_data. */ -#ifdef CONFIG_X86_CMPXCHG64 -#define arch_cmpxchg64(ptr, o, n) \ - ((__typeof__(*(ptr)))__cmpxchg64((ptr), (unsigned long long)(o), \ - (unsigned long long)(n))) -#define arch_cmpxchg64_local(ptr, o, n) \ - ((__typeof__(*(ptr)))__cmpxchg64_local((ptr), (unsigned long long)(o), \ - (unsigned long long)(n))) -#define arch_try_cmpxchg64(ptr, po, n) \ - __try_cmpxchg64((ptr), (unsigned long long *)(po), \ - (unsigned long long)(n)) -#endif +union __u64_halves { + u64 full; + struct { + u32 low, high; + }; +}; + +#define __arch_cmpxchg64(_ptr, _old, _new, _lock) \ +({ \ + union __u64_halves o = { .full = (_old), }, \ + n = { .full = (_new), }; \ + \ + asm volatile(_lock "cmpxchg8b %[ptr]" \ + : [ptr] "+m" (*(_ptr)), \ + "+a" (o.low), "+d" (o.high) \ + : "b" (n.low), "c" (n.high) \ + : "memory"); \ + \ + o.full; \ +}) + + +static __always_inline u64 __cmpxchg64(volatile u64 *ptr, u64 old, u64 new) +{ + return __arch_cmpxchg64(ptr, old, new, LOCK_PREFIX); +} -static inline u64 __cmpxchg64(volatile u64 *ptr, u64 old, u64 new) +static __always_inline u64 __cmpxchg64_local(volatile u64 *ptr, u64 old, u64 new) { - u64 prev; - asm volatile(LOCK_PREFIX "cmpxchg8b %1" - : "=A" (prev), - "+m" (*ptr) - : "b" ((u32)new), - "c" ((u32)(new >> 32)), - "0" (old) - : "memory"); - return prev; + return __arch_cmpxchg64(ptr, old, new,); } -static inline u64 __cmpxchg64_local(volatile u64 *ptr, u64 old, u64 new) +#define __arch_try_cmpxchg64(_ptr, _oldp, _new, _lock) \ +({ \ + union __u64_halves o = { .full = *(_oldp), }, \ + n = { .full = (_new), }; \ + bool ret; \ + \ + asm volatile(_lock "cmpxchg8b %[ptr]" \ + CC_SET(e) \ + : CC_OUT(e) (ret), \ + [ptr] "+m" (*(_ptr)), \ + "+a" (o.low), "+d" (o.high) \ + : "b" (n.low), "c" (n.high) \ + : "memory"); \ + \ + if (unlikely(!ret)) \ + *(_oldp) = o.full; \ + \ + likely(ret); \ +}) + +static __always_inline bool __try_cmpxchg64(volatile u64 *ptr, u64 *oldp, u64 new) { - u64 prev; - asm volatile("cmpxchg8b %1" - : "=A" (prev), - "+m" (*ptr) - : "b" ((u32)new), - "c" ((u32)(new >> 32)), - "0" (old) - : "memory"); - return prev; + return __arch_try_cmpxchg64(ptr, oldp, new, LOCK_PREFIX); } -static inline bool __try_cmpxchg64(volatile u64 *ptr, u64 *pold, u64 new) +static __always_inline bool __try_cmpxchg64_local(volatile u64 *ptr, u64 *oldp, u64 new) { - bool success; - u64 old = *pold; - asm volatile(LOCK_PREFIX "cmpxchg8b %[ptr]" - CC_SET(z) - : CC_OUT(z) (success), - [ptr] "+m" (*ptr), - "+A" (old) - : "b" ((u32)new), - "c" ((u32)(new >> 32)) - : "memory"); - - if (unlikely(!success)) - *pold = old; - return success; + return __arch_try_cmpxchg64(ptr, oldp, new,); } -#ifndef CONFIG_X86_CMPXCHG64 +#ifdef CONFIG_X86_CMPXCHG64 + +#define arch_cmpxchg64 __cmpxchg64 + +#define arch_cmpxchg64_local __cmpxchg64_local + +#define arch_try_cmpxchg64 __try_cmpxchg64 + +#define arch_try_cmpxchg64_local __try_cmpxchg64_local + +#else + /* * Building a kernel capable running on 80386 and 80486. It may be necessary * to simulate the cmpxchg8b on the 80386 and 80486 CPU. */ -#define arch_cmpxchg64(ptr, o, n) \ -({ \ - __typeof__(*(ptr)) __ret; \ - __typeof__(*(ptr)) __old = (o); \ - __typeof__(*(ptr)) __new = (n); \ - alternative_io(LOCK_PREFIX_HERE \ - "call cmpxchg8b_emu", \ - "lock; cmpxchg8b (%%esi)" , \ - X86_FEATURE_CX8, \ - "=A" (__ret), \ - "S" ((ptr)), "0" (__old), \ - "b" ((unsigned int)__new), \ - "c" ((unsigned int)(__new>>32)) \ - : "memory"); \ - __ret; }) - - -#define arch_cmpxchg64_local(ptr, o, n) \ -({ \ - __typeof__(*(ptr)) __ret; \ - __typeof__(*(ptr)) __old = (o); \ - __typeof__(*(ptr)) __new = (n); \ - alternative_io("call cmpxchg8b_emu", \ - "cmpxchg8b (%%esi)" , \ - X86_FEATURE_CX8, \ - "=A" (__ret), \ - "S" ((ptr)), "0" (__old), \ - "b" ((unsigned int)__new), \ - "c" ((unsigned int)(__new>>32)) \ - : "memory"); \ - __ret; }) +#define __arch_cmpxchg64_emu(_ptr, _old, _new, _lock_loc, _lock) \ +({ \ + union __u64_halves o = { .full = (_old), }, \ + n = { .full = (_new), }; \ + \ + asm volatile(ALTERNATIVE(_lock_loc \ + "call cmpxchg8b_emu", \ + _lock "cmpxchg8b %[ptr]", X86_FEATURE_CX8) \ + : [ptr] "+m" (*(_ptr)), \ + "+a" (o.low), "+d" (o.high) \ + : "b" (n.low), "c" (n.high), "S" (_ptr) \ + : "memory"); \ + \ + o.full; \ +}) + +static __always_inline u64 arch_cmpxchg64(volatile u64 *ptr, u64 old, u64 new) +{ + return __arch_cmpxchg64_emu(ptr, old, new, LOCK_PREFIX_HERE, "lock; "); +} +#define arch_cmpxchg64 arch_cmpxchg64 + +static __always_inline u64 arch_cmpxchg64_local(volatile u64 *ptr, u64 old, u64 new) +{ + return __arch_cmpxchg64_emu(ptr, old, new, ,); +} +#define arch_cmpxchg64_local arch_cmpxchg64_local + +#define __arch_try_cmpxchg64_emu(_ptr, _oldp, _new, _lock_loc, _lock) \ +({ \ + union __u64_halves o = { .full = *(_oldp), }, \ + n = { .full = (_new), }; \ + bool ret; \ + \ + asm volatile(ALTERNATIVE(_lock_loc \ + "call cmpxchg8b_emu", \ + _lock "cmpxchg8b %[ptr]", X86_FEATURE_CX8) \ + CC_SET(e) \ + : CC_OUT(e) (ret), \ + [ptr] "+m" (*(_ptr)), \ + "+a" (o.low), "+d" (o.high) \ + : "b" (n.low), "c" (n.high), "S" (_ptr) \ + : "memory"); \ + \ + if (unlikely(!ret)) \ + *(_oldp) = o.full; \ + \ + likely(ret); \ +}) + +static __always_inline bool arch_try_cmpxchg64(volatile u64 *ptr, u64 *oldp, u64 new) +{ + return __arch_try_cmpxchg64_emu(ptr, oldp, new, LOCK_PREFIX_HERE, "lock; "); +} +#define arch_try_cmpxchg64 arch_try_cmpxchg64 + +static __always_inline bool arch_try_cmpxchg64_local(volatile u64 *ptr, u64 *oldp, u64 new) +{ + return __arch_try_cmpxchg64_emu(ptr, oldp, new, ,); +} +#define arch_try_cmpxchg64_local arch_try_cmpxchg64_local #endif diff --git a/arch/x86/include/asm/cmpxchg_64.h b/arch/x86/include/asm/cmpxchg_64.h index 44b08b53ab32..5e241306db26 100644 --- a/arch/x86/include/asm/cmpxchg_64.h +++ b/arch/x86/include/asm/cmpxchg_64.h @@ -20,6 +20,12 @@ arch_try_cmpxchg((ptr), (po), (n)); \ }) +#define arch_try_cmpxchg64_local(ptr, po, n) \ +({ \ + BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ + arch_try_cmpxchg_local((ptr), (po), (n)); \ +}) + union __u128_halves { u128 full; struct { @@ -62,7 +68,7 @@ static __always_inline u128 arch_cmpxchg128_local(volatile u128 *ptr, u128 old, asm volatile(_lock "cmpxchg16b %[ptr]" \ CC_SET(e) \ : CC_OUT(e) (ret), \ - [ptr] "+m" (*ptr), \ + [ptr] "+m" (*(_ptr)), \ "+a" (o.low), "+d" (o.high) \ : "b" (n.low), "c" (n.high) \ : "memory"); \ diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h index cde8357bb226..a053c1293975 100644 --- a/arch/x86/include/asm/qspinlock.h +++ b/arch/x86/include/asm/qspinlock.h @@ -85,6 +85,8 @@ DECLARE_STATIC_KEY_TRUE(virt_spin_lock_key); #define virt_spin_lock virt_spin_lock static inline bool virt_spin_lock(struct qspinlock *lock) { + int val; + if (!static_branch_likely(&virt_spin_lock_key)) return false; @@ -94,10 +96,13 @@ static inline bool virt_spin_lock(struct qspinlock *lock) * horrible lock 'holder' preemption issues. */ - do { - while (atomic_read(&lock->val) != 0) - cpu_relax(); - } while (atomic_cmpxchg(&lock->val, 0, _Q_LOCKED_VAL) != 0); + __retry: + val = atomic_read(&lock->val); + + if (val || !atomic_try_cmpxchg(&lock->val, &val, _Q_LOCKED_VAL)) { + cpu_relax(); + goto __retry; + } return true; } diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h index ef9697f20129..0a985784be9b 100644 --- a/arch/x86/include/asm/qspinlock_paravirt.h +++ b/arch/x86/include/asm/qspinlock_paravirt.h @@ -25,9 +25,9 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text"); * * void __lockfunc __pv_queued_spin_unlock(struct qspinlock *lock) * { - * u8 lockval = cmpxchg(&lock->locked, _Q_LOCKED_VAL, 0); + * u8 lockval = _Q_LOCKED_VAL; * - * if (likely(lockval == _Q_LOCKED_VAL)) + * if (try_cmpxchg(&lock->locked, &lockval, 0)) * return; * pv_queued_spin_unlock_slowpath(lock, lockval); * } @@ -40,10 +40,9 @@ __PV_CALLEE_SAVE_REGS_THUNK(__pv_queued_spin_unlock_slowpath, ".spinlock.text"); #define PV_UNLOCK_ASM \ FRAME_BEGIN \ "push %rdx\n\t" \ - "mov $0x1,%eax\n\t" \ + "mov $" __stringify(_Q_LOCKED_VAL) ",%eax\n\t" \ "xor %edx,%edx\n\t" \ LOCK_PREFIX "cmpxchg %dl,(%rdi)\n\t" \ - "cmp $0x1,%al\n\t" \ "jne .slowpath\n\t" \ "pop %rdx\n\t" \ FRAME_END \ |